1. Field of the Invention
This invention relates to an air nozzle for fasciated yarn spinning. More specifically, this invention relates to an air nozzle utilized for continuously imparting false-twists to a fiber bundle supplied from a pair of delivery rollers such as front draft rollers of a draft means, thereby entangling the surface portion fibers of the fiber bundle around the core portion thereof to form a so-called "fasciated yarn".
2. Description of the Prior Art
In fasciated yarn spinning, it is necessary to effectively suck a fiber bundle attenuated by draft rollers into an air nozzle and to false-twist it therein. If the suction is not sufficient, part of the fiber bundle supplied from the front draft rollers is not smoothly introduced into the air nozzle but is wound onto the rollers by the sticking of the fibers to the roller surface or blown away by the air streams accompanying the high speed rotation of the rollers. This winding of the fibers onto the rollers or blowing away of the fibers causes trouble in the spinning operation, contamination of the working environment, and reduction of the material yield.
In Japanese Examined Patent Publication (Kokoku) No. 43-28250, a device is disclosed in which a suction nozzle for sucking a fiber bundle is provided downstream of a pair of delivery rollers and, further, another nozzle for twisting the fiber bundle is provided downstream of the suction nozzle. According to the above-mentioned device, the suction effect is considerably improved by the independent suction nozzle. However, the device suffers from many problems, such as the increased size of the overall installation due to the additional twisting nozzle, troublesome maintenance; and increased air consumption.
On the other hand, in Japanese Unexamined Patent Publication (Kokai) No. 53-90433, there is disclosed a device having only one nozzle utilized for simultaneously sucking and twisting a fiber bundle. However, the nozzle does not satisfactorily perform well-balanced sucking and twisting because of its structure. Particularly, the suction effect is insufficient due to its conical-shaped inlet structure.